Conventionally, as a vacuum forming device hardly affected by outside air, one has been disclosed which has upper and lower chamber boxes in which a workpiece is formed. The upper and lower chamber boxes can be joined to and separated from each other, the upper chamber box includes a heater that heats the workpiece in the joined chamber boxes (refer to Patent Document 1).
According to the disclosure, the workpiece is heated by the heater in the joined chamber boxes and a near infrared heater is used as the beater, so that the workpiece is heated and formed in a closed space. Thus a vacuum forming device is provided which is hardly affected by outside air during forming compared with conventional devices.